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Parameter Identification of Ships Maneuvering (An ID-Posed Problem Formulation) 船舶机动参数辨识(ID-Posed Problem)
Day 1 Thu, June 11, 1992 Pub Date : 1992-06-11 DOI: 10.5957/attc-1992-002
G. Zilman
{"title":"Parameter Identification of Ships Maneuvering (An ID-Posed Problem Formulation)","authors":"G. Zilman","doi":"10.5957/attc-1992-002","DOIUrl":"https://doi.org/10.5957/attc-1992-002","url":null,"abstract":"Attempts to reduce the difference between the results of mathematical simulations and ship maneuvering trials by means of solving the inverse problem of dynamics generally encounter considerable difficulties. Maybe the main obstacle for system identifiability problems is their instability, which results in the nonrealistic values of the hydrodynamical coefficients.\u0000 A practical method for estimating parameters of the mathematical model of the ship by means of solving the consequence of direct problems is here proposed. The method is based on minimazing the vector of cost functions, which represents the '\"distance” between the object and it's mathematical model. This method allows to take into account the physical restrictions imposed on the hydrodynamical coefficients and to select the Pareto-optimal solution which satisfy all required functional constraints and thus, to avoid the occurrence of \"cancellation effects.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"834 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116150402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Computation of the Hydrodynamic Forces and Moments Developed on a Body of Revolution at Combined Angles of Attack and Angles of Drift and Yawing Angular Velocities 攻角、漂移角和偏航角速度联合作用下公转体的水动力和力矩计算
Day 1 Thu, June 11, 1992 Pub Date : 1992-06-11 DOI: 10.5957/attc-1992-011
Y. Hong
{"title":"Computation of the Hydrodynamic Forces and Moments Developed on a Body of Revolution at Combined Angles of Attack and Angles of Drift and Yawing Angular Velocities","authors":"Y. Hong","doi":"10.5957/attc-1992-011","DOIUrl":"https://doi.org/10.5957/attc-1992-011","url":null,"abstract":"The accurate prediction of the hydrodynamic forces and moments developed on the hull and appendages of a submerged vehicle is required for determining its stability, control, and maneuvering characteristics. Various analytical methods have been developed to make these predictions, including those of computational fluid dynamics, but none of them have been totally successful. This is because it is particularly difficult to accurately determine both the distribution of the velocity over the surface of the hull and the location of the separation lines. The location of the lines of separation has an important effect on the magnitude of the hydrodynamic forces and moments developed on the hull.\u0000 The present method is an extension of the technique discussed in Reference 1. It is assumed that the total hydrodynamic force and moment can be divided into inviscid and viscous parts. The inviscid part of the forces and moments is computed using three dimensional potential theory. The body surface is discretized with many surface elements and the unknown strengths of the source and sink at each surface element are assumed to be constant. The velocities at surface elements are computed and saved for later computation of the viscous forces and moments. The viscous part of the forces and moments is computed with the application of the boundary layer theory for laminar and turbulent flows. The axial force is computed with the method of developed by Young (2). The lateral forces and its moments are computed under the assumption that there is separation in the two-dimensional cross flow. The boundary layer equation is solved to the separation point and the frictional drag is integrated to compute frictional force. Furthermore, it is assumed that a constant pressure is acting on the two dimensional section beyond the separation point.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126013485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Propeller Erosion Reduction with an Asymmetric Preswirl Stator 非对称前置涡定子减少螺旋桨冲蚀
Day 1 Thu, June 11, 1992 Pub Date : 1992-06-11 DOI: 10.5957/attc-1992-022
T. B. Smith, K. Remmers
{"title":"Propeller Erosion Reduction with an Asymmetric Preswirl Stator","authors":"T. B. Smith, K. Remmers","doi":"10.5957/attc-1992-022","DOIUrl":"https://doi.org/10.5957/attc-1992-022","url":null,"abstract":"This paper presents the results of a series of model-scale tests of the erosion-reduction capabilities of a partial-span asymmetric preswirl stator on the propeller of a large United States Coast Guard (USCG) patrol boat. The propeller and stator were tested at one-third scale (A - 3 .2) in the DTRC 36-inch Variable Pressure Water Tunnel (VPWT). A single shaft strut upstream of the propeller and a shaft inclination of 9.25° simulated the full-scale propeller flow field. Cavitation erosion tendency was investigated using an erodable coating painted on the propeller blades. Stator performance was evaluated in a series of model tests at 30 knots, both with and without the currently- installed cavitation relief holes, using three different series of stator blade angle of attack settings These high Reynolds number experiments showed that the blade root erosion tendency was almost completely eliminated by the preswirl stator with the cavitation relief holes at the propeller blade root closed. A lesser degree of erosion relief was provided by the preswirl stator with the cavitation relief holes open.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125051708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Development of a Waterjet Propulsor for the Marine Corps High Water Speed Landing Craft Application 海军陆战队高水速登陆艇用喷水推进器的研制
Day 1 Thu, June 11, 1992 Pub Date : 1992-06-11 DOI: 10.5957/attc-1992-014
J. Stricker, A. J. Becnel, J. Purnell
{"title":"Development of a Waterjet Propulsor for the Marine Corps High Water Speed Landing Craft Application","authors":"J. Stricker, A. J. Becnel, J. Purnell","doi":"10.5957/attc-1992-014","DOIUrl":"https://doi.org/10.5957/attc-1992-014","url":null,"abstract":"An advanced high performance waterjet propulsor was developed as part of the Marine Corps Surface Mobility technology development effort. Design optimization, performance estimating, and hydrodynamic design procedures are described for a propulsion unit required to meet specified thrust, power, and envelope characteristics. Testing of a 10-inch scale model and trials of the full scale propulsion units in both the HWSTD (High Water Speed Technology Demonstrator) and PSD (Propulsion System Demonstrator) developmental vehicles are described and performance data correlations presented.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114791083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The Large Cavitation Channel 大空化通道
Day 1 Thu, June 11, 1992 Pub Date : 1992-06-11 DOI: 10.5957/attc-1992-024
R. Etter, M. Wilson
{"title":"The Large Cavitation Channel","authors":"R. Etter, M. Wilson","doi":"10.5957/attc-1992-024","DOIUrl":"https://doi.org/10.5957/attc-1992-024","url":null,"abstract":"The Large Cavitation Channel (LCC) of the David Taylor Model Basin, CDNSWC, is a large variable pressure water tunnel recently put into operation in Memphis, Tennessee. This facility incorporates many of the latest technological concepts in the design of hydrodynamic and hydroacoustic test facilities. This paper discusses a number of the key technical and design issues that had to be addressed first in the basic specifications and then in the final features as constructed. Issues include: size, shape, speed. pressure range, turbulence management, turning vanes, contraction and diffuser, main pump impeller, hydroacoustic considerations of noise sources, quieting, and noise measurement; and operational features involving model size, powering, and measurement of model propulsor thrust and torque.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"304 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121676588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
SHIPMO Seakeeping Predictions and Correlations SHIPMO耐海性预测和相关性
Day 1 Thu, June 11, 1992 Pub Date : 1992-06-11 DOI: 10.5957/attc-1992-006
B. Menon, J. Vienneau
{"title":"SHIPMO Seakeeping Predictions and Correlations","authors":"B. Menon, J. Vienneau","doi":"10.5957/attc-1992-006","DOIUrl":"https://doi.org/10.5957/attc-1992-006","url":null,"abstract":"Experience with the strip theory-based numerical seakeeping performance prediction model SHIPMO is described with applications ranging from fast surface vessels to unconventional hull forms such as icebreakers. A brief history of the model's development, its salient features and examples of validations are given. Four comparisons between predictions and measurements from scale model tests are illustrated, along with limited comparisons against predictions of other standard seakeeping models. These include pitch and heave motions in head seas, unstabilized roll motions in beam seas, as well as motions in stern quartering seas. Correlations have been made both for regular as well as irregular waves. It is shown that regular wave pitch, heave and roll RAO's correlate well, while motions in irregular seas correlate to a lesser degree. Comparisons with other models show that SHIPMO predictions are as good as those from other established programs based on strip theory.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"493 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133117875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Radar Imaging of Surface Ship Wake Flows 水面舰船尾流的雷达成像
Day 1 Thu, June 11, 1992 Pub Date : 1992-06-11 DOI: 10.5957/attc-1992-034
K. Nicolas, C. S. Weller, W. Lindenmuth, B. Cheng
{"title":"Radar Imaging of Surface Ship Wake Flows","authors":"K. Nicolas, C. S. Weller, W. Lindenmuth, B. Cheng","doi":"10.5957/attc-1992-034","DOIUrl":"https://doi.org/10.5957/attc-1992-034","url":null,"abstract":"Promising results have been achieved in the development of radar diagnostic techniques for the mapping of water surface velocities in the laboratory environment of the Maneuvering and Sea Keeping Basin (MASK) at DTMB. High resolution measurements, with the Radar Image Modeling System (RIMS ) instrumentation radar, mapped the structure of the transverse surface velocities of the wake from a self-propelled ship model. The wake center has a broad distribution of transverse velocities with speeds of typically 10 cm/sec. The outer wake exhibits higher transverse velocities, e.g. 25 cm/ sec, which are interpreted as the sum of the water velocity and the capillary wave phase speed.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125742949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Run Length and Statistical Error Estimation for Seakeeping Tests and Trials 耐波性试验和试验的航行长度和统计误差估计
Day 1 Thu, June 11, 1992 Pub Date : 1992-06-11 DOI: 10.5957/attc-1992-008
R. D. Pierce
{"title":"Run Length and Statistical Error Estimation for Seakeeping Tests and Trials","authors":"R. D. Pierce","doi":"10.5957/attc-1992-008","DOIUrl":"https://doi.org/10.5957/attc-1992-008","url":null,"abstract":"A seaway and the resulting responses of models or full-scale craft are random processes. The accuracy of the final results depends heavily on the length of the test runs. Therefore in the planning, execution, and evaluation phases of a seakeeping test or trial, run length and its effect on the accuracy of the data must be accounted for. Two basic problem areas exist:\u0000 1. Run length estimation prior to a test or trial so that the mission can be carried out efficiently, and data gathered to a desired accuracy.\u0000 2. Error estimation for data taken in the past to determine what accuracy level was reached. The run length directly affects the level of accuracy or confidence in the processed results. This accuracy level is, in turn, a trade-off between the task priority and the statistical variability of the input medium (the seaway in this case) A higher priority mission will call for a higher data accuracy and longer run length while a changing sea condition will put constraints on this accuracy. In effect, items 1 and 2 must be considered in all missions to aid in pre-mission planning and to better understand the reliability of data gathered from a previous mission. This paper presents and describes methods to:\u0000 1. Determine the auto spectrum effective peak frequencies and half-power bandwidths needed to estimate run length and statistical error for given data samples.\u0000 2. Estimate random process mean values, standard deviations, variance, auto spectra and Response Amplitude Operators (RAO' s).\u0000 3. Estimate the statistical errors and run lengths associated with the mean value, standard deviation, variance, auto spectra and RAO's of a random process.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122020180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Experience with Hot-Film Anemometry for Ship Model Nominal Wake Survey in a Towing Tank 用热膜风速法测量拖曳舱船模标称尾流的经验
Day 1 Thu, June 11, 1992 Pub Date : 1992-06-11 DOI: 10.5957/attc-1992-015
S. Wu, N. Bose
{"title":"Experience with Hot-Film Anemometry for Ship Model Nominal Wake Survey in a Towing Tank","authors":"S. Wu, N. Bose","doi":"10.5957/attc-1992-015","DOIUrl":"https://doi.org/10.5957/attc-1992-015","url":null,"abstract":"Problems with the calibration and operation of hot-film anemometers in water have prevented their widespread application for towing tank measurements. The potential advantages of their use, in terms of their accuracy compared with pitot tubes and their low coot compared with laser-doppler anemometry, have yet to be fully exploited. Calibration experiments with several hot-film probes were done in a towing tank to investigate their characteristics. After an initial 'burn in' period of about 100 hours of operation, their calibration was found to be stable and repeatable, although it varied with the ambient water temperature.\u0000 Nominal wake survey experiments were conducted be hind a model of a Newfoundland fishing vessel form by using a wedge-shaped single sensor hot-film probe and a dual sensor vee hot-film probe respectively. The model was towed at a speed of l.45m/s, which corresponded to a Froude number of 0.33 and full scale vessel speed of 6.4 knots. Levels of turbulence as well as mean velocity values in the wake were obtained. A comparison is made between sample results obtained by the use of the two different probes.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116022840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
New Apparatus for Captive Model Testing of Submerged Bodies in Coning Motion 一种新的水下运动自保模型试验装置
Day 1 Thu, June 11, 1992 Pub Date : 1992-06-11 DOI: 10.5957/attc-1992-030
E. Lewandowski
{"title":"New Apparatus for Captive Model Testing of Submerged Bodies in Coning Motion","authors":"E. Lewandowski","doi":"10.5957/attc-1992-030","DOIUrl":"https://doi.org/10.5957/attc-1992-030","url":null,"abstract":"A new apparatus has been designed and constructed to measure the hydrodynamic forces and moments on a captive model in coning motion. The apparatus permits examination of the effects of roll angular velocity in combination with other angular and linear velocity components on these forces and moments. The design of the apparatus is described, and some typical results are shown.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125967623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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